The Guantánamo Bay files spell out the Americans' suspicions about individual detainees' involvement with terrorism, their intelligence value and the threat they are considered to pose if released. Photograph: John Moore/Getty Images

The Guantánamo files consists of 759 "detainee assessment" dossiers written between 2002 and 2009 and sent up through the military hierarchy to the US Southern Command headquarters in Miami. They appear to cover all but 20 of the prisoners.

A number of other documents in the cache spell out guidelines for interrogating and deciding the fate of detainees. One, the "JTF-GTMO matrix of threat indicators" details the "indicators" which should be used to "determine a detainee's capabilities and intentions to pose a terrorist threat if the detainee were given the opportunity." Another provides a matrix for deciding whether a prisoner should be held or released.

All the detainee assessments are classified "secret" but sometimes they mention separate, more sensitive "secret compartmented intelligence" (SCI) dossiers held elsewhere.

The most recent prisoner assessments are from January 2009 when Rear-Admiral DM Thomas Jr, who was the Guantánamo commander at the time, protested about the plan to transfer out two Saudis and a Yemeni, all of whom he still regarded as "high risk".

The files spell out the extent of involvement US authorities believe each detainee has had with al-Qaida, the Taliban or other terror groups, an assessment of their intelligence value and the threat they are considered to pose if released. In each case they also make a recommendation for the future detention, release or transfer of the detainee.

Material presented as "evidence" in the assessments must be treated with scepticism as a number of files contain information known to have been extracted under torture, which has in several cases subsequently been found unreliable.

The dossiers allot each prisoner an ISN: internment serial number. These run in chronological sequence from arrival at Guantánamo. No 1, John Walker Lindh, was not interned at Guantánamo, however; as a US citizen he was tried and convicted in the US in 2002. The ISN is prefixed with a nationality. Binyam Mohamed, who is of Ethiopian extraction, has the ISN ET-1458.

The files were shared with the Guardian and US National Public Radio by the New York Times, which says it did not obtain them from WikiLeaks.